is a muscle with four chambers
that contract at regulated intervals to pump blood
throughout the body. These contractions are generated by electricity that passes with very precise speeds through distinct pathways along the fibers of the heart muscle.
This electricity originates from the heart's sinoatrial node, also known as the heart's pacemaker, which is found in the right atrium
at the top half of the heart's upper right chamber. The rate of electrical current discharged by the sinoatrial node, together with nerve
impulses and hormone
levels in the blood, determines a person's heart rate or heart rhythm.
IRREGULAR HEARTBEAT SIGNS AND SYMPTOMS
The normal heart rate for adults runs from between 60 to 100 beats per minute when at rest. This rate is lower for younger people who are more physically fit than most. Each person's heart rate responds differently during exercise, exertion, or other stimuli which include intense emotions.
When the electrical impulses that govern the heart rate start to malfunction, the heart may either start to beat too fast (tachycardia), too slow (bradycardia), irregularly (dysrhythmia), or even pass through abnormal electrical pathways. These group of heart conditions are called arrhythmias, or abnormal heart rhythms.
Arrhythmias are a common occurrence and are normally harmless. People who have irregular heartbeats
experience a fluttering or racing heart, or a sensation as if their hearts may have skipped a beat or two. Even children experience a normal kind of irregular heartbeat called sinus
arrhythmia, which is characterized by a slight acceleration or slowing of the heart rate in relation to the rhythms of their respiration. This condition normally lessens as they grow up.
IRREGULAR HEARTBEAT CAUSES
However, there are some arrhythmias, that can cause annoying, and worse, even seriously fatal symptoms, like coronary heart disease
and cardiac arrest. Some arrhythmias can be signs of other dangerous illnesses, like a stroke or embolus (obstruction of the blood flow). In the U.S. alone, over 850,000 people are treated for these types of arrhythmias each year.
Other causes of irregular heartbeat include an imbalance of electrolytes, like sodium and potassium in the blood; injuries stemming from a heart attack; changes in the heart muscle, and as part of the healing process after heart surgery. Smoking can also result in arrhythmias, as well as caffeine use, and alcohol or drug abuse. In some cases, prescription or over-the-counter medications, some dietary supplements and herbal remedies can trigger irregular heartbeat, as well.
If a person’s heart has incurred some scarring from a previous ailment, like a heart attack
, or if there is a pre-existing heart condition like inadequate blood supply, coronary artery disease, cardiomyopathy (enlargement of the ventricular walls), or valvular heart disease (narrowing of the heart valves), these can cause a destabilization of the electrical impulses in the heart, resulting in the development of arrhythmia.
IRREGULAR HEARTBEAT RISK FACTOR
The risks for developing an arrhythmia increases with age, when the heart muscle starts to weaken and affects the way electrical impulses pass through the pathways. People who have congenital (at birth) heart problems, thyroid conditions (hyperthyroidism or hypothyroidism), high blood pressure
, digestive disorders like diarrhea
, and obstructive sleep apnea have a higher risk of acquiring an irregular heartbeat.
Even fatigue, hunger, pain, exercise and emotional stress can trigger arrhythmia, although in these cases, the irregular heartbeat tends to resolve itself after the affecting stimuli has ceased.
Other symptoms include a fluttering sensation of the heart, pounding in the chest, shortness of breath, a feeling of discomfort in the chest, and fatigue.
Some arrhythmias do not carry any symptoms and are not a cause for concern. The most common symptom is an increased awareness of heartbeat, also known as palpitations. Palpitations can occur either frequently, infrequently, and can also go on continuously. These type of arrhythmias can cause annoyance, and are mostly harmless.
When an arrhythmia causes the heart to beat too slow or two fast to be able supply what the body needs, a person may suffer from low blood pressure and experience lightheadedness, dizziness
, and may even faint.
Some arrhythmias signal the presence of more serious ailments, and some even increase the risk of certain conditions, like strokes or embolisation, heart failure and cardiac death. Sudden Arrhythmia Death Syndome (SADS) is sudden death from a cardiac arrest caused by arrhythmia. Although SADS can also be due to other causes, it commonly stems from coronary artery disease.
Image: Irregular Heartbeat
IRREGULAR HEARTBEAT DIAGNOSIS
The doctor can determine whether the arrhythmia is acute or chronic by taking the person’s medical history, and to determine whether they are sensitive to certain substances like alcohol, caffeine and other drugs. The doctor can also take a persons pulse or use a stethoscope to determine whether the heart rate is regular or irregular.
IRREGULAR HEARTBEAT TEST
The most specific test to assess a person’s heart rhythm is through an electrocardiogram
(ECG). Another method is through Holter monitor
, an EKG
which can be worn for a day to record any instances of irregular heartbeat as they occur during a 24-hour period.
Other tests used to diagnose arrhythmia include a Stress Test
(monitoring the heart during exercise), the use of an Event Monitor (a portable ECG), an Echocardiogram
(uses sound waves to take images of heart’s movements, size and structure), cardiac catherization (thin tubes with electrodes are threaded into some blood vessels
of the heart), an Electrophysiology study (EPS), and a head-up tilt table test
(used for patients who suffer fainting spells).
IRREGULAR HEARTBEAT TREATMENT
Treating arrhythmias will depend on the type of irregular heartbeat a person has, and how serious the case is. Some arrhythmias will not require treatment at all, while others necessitate major surgical procedures, medication and a change in lifestyle.
Irregular heartbeat can be treated using Cardioversion, where an electrical current is applied across the heart’s chest wall to treat pulsed ventricular tachycardia
(fast heartbeat caused by abnormal electrical impulses). Defibrillation, where even more electricity can be delivered, is used to remedy ventricular fibrillation
, a condition where a confusion
of electrical impulses trigger the heart's ventricles to quiver uncontrollably instead of pumping blood. Ventricular fibrillation is believed to be one of the causes of sudden cardiac death (SAD) that kills around 300,000 Americans each year.
Cardiac pacing may also be applied for sufferers of bradycardia, or very slow hearbeats. This is usually indicated for arrhythmias caused by a drug overdose or myocardial infarction
(heart attack). Sometimes, a pacemaker has to be inserted into the heart for patients who have severe bradycardia.
A cardiologist, who specializes in heart ailments, may also treat a patient with pulmonary vein isolation, a procedure used to treat atrial fibrillation
, which is a kind of arrhythmia which causes the heart's atrial chambers
to beat abnormally.
Other treatments include implanting a cardioverter-defibrillator (ICD) to monitor the heart's rhythm and to deliver a spurt of energy to the heart when it stars beating irregularly; catheter ablation, where electrical energy in high frequencies is directed through a catheter and targeted at areas of the heart with irregular rhythms; in cases where there is a pre-existing heart condition which causes the arrhythmia, surgical procedures like the Maze procedure, ventricular aneurysm surgery or a coronary bypass may be needed to correct the problem.
There are also many drugs that doctors prescribe to treat troublesome arrhythmias. These include antiarrhythmic medications which are used to control a person's heart rate, like beta blockers. Anticoagulants and antiplatelet drugs lower the risk of blood clots
. Examples of these are blood thinners like warfarin
, and the generic aspirin
IRREGULAR HEARTBEAT PREVENTION
To prevent and lower the risks of life-threatening arrhythmias, especially those that are caused by underlying heart conditions, certain lifestyle changes should be affected. This includes avoiding activities which can trigger the onset of irregular heartbeat, cutting down on alcohol or caffeine intake, stopping a smoking habit, and avoiding cough
or cold medicines that may contain alcohol or stimulants.
The doctor may also recommend a healthy diet rich in food that is good for the heart, regular exercise, and reducing the levels of stress in a patient's life.
The prognosis for arrhythmia will depend on the kind of irregular heartbeat a person has, whether is harmless or potentially dangerous, like ventricular tachycardia or ventricular fibrillation that can cause sudden death. It will also depend on the heart's pumping ability, and a person's response to the arrhythmia.
A new system has recently been developed to combine computerized tomography (CT) and magnetic resonance imaging
(MRI) scans of the heart during the performance of a catheter ablation procedure. Current research at the University of California in San Francisco Medical Center is looking at mapping and ablation of patients diagnosed with atrial arrhythmias. It is also trying out new drug therapies to remedy potentially dangerous arrhythmias which cause sudden cardiac death.